Not Applicable
(1) Field of the Invention
The present invention relates to a conveyor motor for use in a differential impulse conveyor. In particular, the present invention relates to a pneumatic conveyor motor which uses pneumatic bellows to provide the reciprocating motion for moving the objects along the conveyor.
(2) Description of the Related Art
Differential impulse conveyors, also known as liner motion conveyors, move objects along a surface or tray by varying the direction and speed of the movement of the surface. The conveyor motor moves the conveyor surface slowly in a forward direction to convey the objects forward. The conveyor motor then moves the conveyor surface quickly in the opposite or backward direction. As the conveyor surface is quickly moved backwards, the objects slide along the surface such that the objects remain in the forward position. The slow forward and fast rearward motion is repeated to move the objects along the surface in the forward direction.
The related art has shown various types of differential impulse conveyors where the conveying surface is driven in the forward direction at a slow speed and is driven in the backward direction at a higher speed. Illustrative are U.S. Pat. Nos. 5,794,757 to Svejkowsky et al.; 5,850,906 to Dean and U.S. Pat. No. 6,209,713 to Takahashi et al. The conveyors use a variety of different drive motors. However, none of the conveyors use bellows as the drive mechanism.
U.S. Pat. No. 1,146,947 to Norton; U.S. Pat. No. 2,214,755 to Tafel; U.S. Pat. No. 2,473,193 to Campion; and U.S. Pat. No. 4,508,208 to Preedy describe pneumatic transporters or conveyors which use pneumatic cylinders, pistons and seals to provide the drive or momentum for the conveyor. A fluid such as air can be used to move the pistons. However, none of the patents show the use of pneumatic bellows.
Also, of interest is U.S. Pat. No. 2,378,979 to Burt which describes a vibrating conveyor which uses a pressure responsive element such as a bellow or flexible diaphragm to create vibrations which are transferred to a conveyor table. The conveyor of this reference is a vibration conveyor rather than a differential impulse conveyor as in the present invention. Further, the pressure response element of this patent is operated by water.
There remains the need for a differential impulse conveyor which uses pneumatic bellows as the drive motor. Bellows have inherent qualities of low maintenance, tolerance to lateral misalignment, high resistance to contamination and frictionless stroke. Bellows are also capable of generating high forces and need no lubrication. Thus, the use of bellows enables the present invention to be inexpensive to construct and inexpensive to maintain.
The present invention relates to a differential impulse conveyor having a conveyor motor which uses bellows to provide the driving force for the conveyor. The conveyor is intended to be used to move objects such as parts and/or scrap out of a stamping press. The conveyor includes a housing within which is mounted the conveyor motor. The conveyor motor has a pair of first and second bellows, a drive plate and a fluid control system. The bellows are mounted at the first end to end plates. The end plates have holes which align with the inlet of the bellows to allow for inflating the bellows. The end plates are connected together by a pair of upper guide rods and a pair of lower guide rods. The drive plate is mounted between the first and second bellows adjacent the second ends of the bellows. The drive plate is movably mounted on the guide rods. A follower plate can also be provided adjacent the second end plate on a side opposite the bellows. The follower plate is movably mounted on the upper guide rods. The conveyor plate is mounted to the top ends of the drive plate and the follower plate. The fluid control system includes a main control valve, first and second valves, a first and second limit switch, and a flow control valve. The main control valve is connected to the first and second valves which are connected to the inlets of the bellows. The main control valve controls the flow of fluid to the bellows from the fluid source. The fluid is preferably compressed air. The limit switches are connected to the main control valve and are mounted adjacent the end plates. In one (1) embodiment, the limit switches are pneumatic switches and are provided with fluid from the fluid source. The inlets of the limit switch are connected to the fluid source and the outlets of the limit switches are connected to the main control valve. The flow control valve can be provided in the fluid line between the outlet of either of the limit switches and the main control valve. The flow control valve alters and controls the signal provided to the main control valve by the limit switch. The conveyor can be a bi-directional conveyor. In this embodiment, flow control valves are provided for each of the limit switches. A bi-directional control switch is provided to allow for bypassing one of the flow control valves depending on the direction of the conveyor.
To move objects toward the second end of the conveyor, fluid from the fluid supply is provided through the main control valve through the first valve and to the inlet of the first bellows. As the first bellows inflates, the drive plate with the conveyor plate moves toward the second bellows. The drive plate continues to move until the drive plate contacts the second limit switch and activates the second limit switch. Upon activation, the second limit switch sends a signal to the main control valve. The main control valve stops the flow of fluid to the first bellows and starts the flow of fluid to the second bellows. As the second bellow inflates, the drive plate moves toward the first bellows and causes the first bellows to deflate. The drive plate continues to move until the drive plate contacts the first limit switch and activates the first limit switch. Upon activation, the first limit switch sends a signal to the main control valve. The first flow control valve located in the line between the first limit switch and the main control valve alters and controls the signal from the first limit switch to the main control valve. The first flow control valve alters the signal such that the switching or activation of the main control valve is delayed such that there is a pause between the time the fluid flow is stopped to the second bellows and the fluid flow begins to the first bellows. This delay causes a pause in the motion of the drive plate and thus, the conveyor plate. The pause in motion allows the conveyor plate to reestablish contact with the objects on the conveyor plate. The flow control valve also alters the signal such that the rate of flow of the fluid to the first bellows gradually increases. This allows for slower inflation of the first bellows and slower movement of the conveyor plate. To move objects in the other direction, the bi-directional switch is activated such that the first flow control valve is bypassed and the second control valve is operational. The second flow control valve alters the signal from the second limit switch to the main control valve similar to the first flow control valve such that the rate of fluid flow to the second bellows is less than the rate of fluid flow to the first bellows.
The present invention relates to a conveyor motor for moving a conveyor plate to move objects along the conveyor plate, which comprises: a drive plate movably mounted, having a first side and a second side and connected to the conveyor plate; a first bellows mounted adjacent the first side of the drive plate and configured to contact the first side of the drive plate and having an inlet; a second bellows mounted adjacent the second side of the drive plate and configured to contact the second side of the drive plate and having an inlet; and a main control valve in fluid communication with the inlet of the first bellows and the inlet of the second bellows wherein the main control valve is configured such that a rate of inflation of the second bellows is greater than a rate of inflation of the first bellows.
Further, the present invention relates to a conveyor for moving objects, which comprises: a housing; a drive plate having a first side and a second side and movably mounted in the housing; a first bellows mounted in the housing adjacent the first side of the drive plate and configured to contact the first side of the drive plate and having an inlet; a second bellows mounted in the housing adjacent the second side of the drive plate and configured to contact the second side of the drive plate and having an inlet; and a main control valve in fluid communication with the inlet of the first bellows and the inlet of the second bellows wherein the main valve is configured such that a rate of inflation of the second bellows is greater than a rate of inflation of the first bellows.
Still further, the present invention relates to a method for moving objects, which comprises: providing a conveyor including a conveyor motor having a drive plate with a first and second side and a conveyor plate connected to the drive plate; a first bellows adjacent to and configured to contact the first side of the drive plate and having an inlet; a second bellows adjacent to and configured to contact the second side of the drive plate, and having an inlet; and a main control valve in fluid communication with the inlet of the first bellows and the inlet of the second bellows; providing a fluid source; connecting the fluid source to the main control valve; activating the main control valve such that fluid flows from the fluid source into the inlet of the first bellows such that the first bellows inflates at a predetermined rate of inflation of the first bellows wherein as the first bellows inflates the first bellows contacts the drive plate and moves the drive plate toward the second bellows; activating the main control valve such that the fluid stops flowing to the first bellows and such that fluid flows from the fluid source into the inlet of the second bellows such that the second bellows inflates at a predetermined rate of inflation wherein as the second bellows inflates, the second bellows contacts the drive plate and moves the drive plate toward the first bellows such that the first bellows deflates wherein the predetermined rate of inflation of the second bellows is greater than the predetermined rate of inflation of the first bellows; activating the main control valve such that the fluid stops flowing to the second bellows and such that fluid flows to the first bellows such that the first bellows is inflated at the predetermined rate of inflation of the first bellows and wherein as the drive plate moves toward the second bellows, the second bellows deflates; and placing the objects on the conveyor plate and repeating steps (e) and (f) to move the objects along the conveyor plate.
The substance and advantages of the present invention will become increasingly apparent by reference to the following drawings and the description.